Multi-row wrapping machine particularly for wrapping confectionery products such as slabs of chocolate and suchlike

ABSTRACT

A multi-row wrapping machine for wrapping products (P) comprising a plurality of wrapping lines or rows (F), adjacent and coplanar to each other, each wrapping row being defined between a common input station ( 2 ) and a respective output station ( 3 ) for wrapped products, the rows developing parallel to each other along a direction of advance from the input station towards the output station, conveying means (N) being provided to convey the products (P), one in line with the other, along each respective wrapping line, the products being fed to the input station ( 2 ) in ranks at a set rate, each product of each rank engaging with each respective wrapping line at the same time. The machine has dragging means provided on each respective wrapping row to drag a respective wrapping film (T) in an unwinding direction, wrapping means to wrap the individual product (P) in wrapping film (T) and also to cut and weld the reciprocally superimposed edges of the wrapper, feeding the wrapped product to the output station ( 3 ). In each wrapping row (F 1 , F 2 , . . . Fn) of the plurality of rows there are separate and distinct means (N 1 , N 2 , . . . Nn) to convey the products (P) from the input station ( 2 ) to the output station ( 3 ), separate and distinct means to feed the respective wrapping film (T) and separate and distinct means to wrap the product (P), so that the entire product moving and wrapping stage, from the input station ( 2 ) to the output station ( 3 ) is operated and controlled along each row (F 1 , F 2 , . . . Fn) independently of the other respective rows.

TECHNICAL FIELD

The present invention concerns a wrapping machine, particularly for wrapping confectionery products such as slabs of chocolate and suchlike, having the characteristics described in the preamble of main claim 1.

BACKGROUND ART

The machine according to the invention is used particularly, although not exclusively, in the technical sector of multi-row wrappers of confectionery products such as bars or slabs of chocolate. Machines of the above-mentioned type are widely used in wrapping lines, in which the individual products are fed to the wrappers from production lines and are moved along on conveyor belts arranged in ranks or groups of ranks spaced apart (ranks in this context mean groups of products aligned in a direction perpendicular to the products' direction of advance). In multi-row wrapping machines each product of a respective rank simultaneously engages with the respective wrapping row so that the entire rank proceeds synchronously through the various stages of movement and wrapping inside the wrapping machine.

Unlike single-row wrapping machines, known through the production of the applicant, multi-row wrapping machines typically have operating motor means and means of controlling the latter capable of serving the entire group of wrapping rows. In other words, the movement of the products along each row is achieved by a single actuating motor means connected with the respective drive means to the members for transportation of the individual wrapping rows. Similarly, in traditional multi-row wrapping machines, the welding and cutting heads of the wrapping film are operated by a single means of motorisation which, via the appropriate drive and redirection members, transfer the motion to the respective end of the corresponding row.

The limitation of these applications consists in the fact that any stoppage of the motorisation devices involves a machine stoppage that impinges on all the wrapping lines, with a heavy penalty as regards the productivity of these machines. On the other hand, existing known arrangements have failed to provide satisfactory solutions, aimed at overcoming the above-mentioned limitations, basically because of the space required and the consequent difficulty of access to the operating members, such aspects preventing the correct performance of the checking, adjustment and maintenance operations required by the wrapping machine.

DISCLOSURE OF THE INVENTION

One of the main aims of the invention is to provide a wrapping machine which is structurally and operationally designed to overcome the limitations described with reference to said known state-of-the-art machines, in particular by offering an operationally reliable, high-productivity solution which at the same time allows easy adjustment and maintenance of the operating and control members.

This and other aims which will appear more clearly below are achieved by a multi-row wrapping machine made in accordance with the attached claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The characteristics and advantages of the invention will be better understood from the following detailed description of one of its preferred embodiments illustrated, by way of indication and in no way limiting, with reference to the attached drawings in which:

FIG. 1 is a partial schematic view of a wrapping machine according to the invention;

FIGS. 2 and 3 are schematic plan top views of the wrapping machine shown in FIG. 1;

FIGS. 4A and 4B are schematic side elevation views along arrows A′ and B′ respectively of FIG. 3;

FIGS. 5 and 6 are front elevation views of a part of the wrapping machine shown in the preceding figures, in two respective operating conditions;

FIG. 7 is a side elevation view of the part shown in FIG. 6;

FIGS. 8 to 15 are partial views of the machine shown in the preceding figures.

PREFERRED EMBODIMENT OF THE INVENTION

With reference to said figures, 1 shows as a whole a multi-row wrapping machine according to the present invention. Machine 1 comprises a plurality of wrapping lines or rows, indicated by F1, F2, . . . Fn, developed parallel and coplanar to each other between an input station 2 and an output station 3, along a direction of advance, marked X in the figures. The ranks of products P to be wrapped, such as for example slabs or bars of chocolate arriving from the production lines located upstream of the wrapping machine, are transported to input station 2. Each wrapping row has a respective conveyor belt N1, N2, . . . , Nn, preferably moved with motorised chain drive (not shown in the figures), by which the products are conveyed towards the output station. Products P of the same rank may be guided to the opposite sides of the input station 2, in order correctly to engage with belts N1-Nn, so that each product in the rank engages with the respective row at the same time. For reasons of sideways-occupied space, belts N1-Nn may diverge for a first section in direction X in order to connect the input station, distinguished by a certain lateral pitch between the products, with the wrapping rows downstream of said first section, in which the pitch between the rows is chosen to be greater. Downstream of said section, belts N1-Nn of the wrapping rows proceed parallel to each other at the pre-selected distance apart until reaching output station 3 in which the products P of the same rank are discharged after having been, at the same time, wrapped.

In the example described here, machine 1 comprises nine wrapping rows F but it is understood that it may comprise a different number, compatible with the space occupied by the wrapping devices and members associated with each respective row.

In order to move the wrapping row conveyor belts N1-Nn there are separate and distinct servomotors that are operationally connected to each row independently of the other rows, so that the stoppage of one or more rows does not cause the other wrapping rows to stop.

In order to wrap the products P the machine comprises, for each wrapping row, a group of reels B onto which a product wrapping film T is wound. More particularly, for each wrapping row F, the respective group comprises a pair of reels 61, 62 between which there is an automatic reel changing device 5, of the same type as those traditionally used in single-row wrappers and which will not therefore be described in detail. It comprises a pair of reel-carrier winders 6, a sensor 7 capable of detecting the final end of the reel film, a means 8 of joining the final edge of film of one reel to the initial edge of the other reel, so as to guarantee the change of reel without requiring the machine to be stopped.

It will be noted how each group of reels is operated by separate and distinct means of feeding and dragging the respective wrapping film, which include respective motor means for dragging the film in the unwinding direction.

For reasons of space, dictated by the number of groups of reels required for the wrapping rows provided, said groups of reels B are located outside rows F with the axes of the reels being parallel to the direction X. Preferably the reels are located on one side of the rows and divided into a first group of four pairs of reels and a second opposing group of five pairs of reels, as illustrated in FIGS. 4A and 4B. Based on this arrangement, the wrapping film of each reel B is dragged along a first section perpendicular to direction X and then redirected 90° back along a second straight section parallel to direction X, until it reaches the corresponding output station. To redirect each film, a respective redirecting arm 9 is positioned at 45° in relation to the directions of the two dragging sections (at an angle of 90° in relation to each other), as clearly shown in FIGS. 2 and 3. The positioning of each redirecting arm 9 can also be adjusted as will clearly appear from the following description, in order to enable the corresponding wrapping film to be dragged into a centred position in relation to the product P to be wrapped. With reference to FIGS. 8 and 9, each redirecting arm 9 is connected to a respective supporting bracket 10 which is guided by engaging in a sliding manner with a guide element 11, in the direction (shown by a Y) perpendicular to direction X. For this purpose each bracket 10 has a respective lead nut 12 which in turn engages in a screwing manner with a corresponding screw 13 connected coaxially to the output shaft of a respective servomotor 14. The connection is such that a pre-selected number of revolutions of the motor 14 corresponds to a pre-set translation of the bracket 10 (thanks to the screw/nut thread connection the rotation of the motor is converted into a translation of the lead nut and therefore the bracket). 15 shows a proximity sensor capable of detecting the position of the bracket 10 in the transverse adjustment travel in direction Y.

In order to centre each wrapping film T there is also, downstream of the corresponding redirecting arm 9, a respective centering device 16 which comprises a first and second pair of sensor means (L1, L2; R1, R2), each pair being arranged to detect the position of one of the respective opposing side edges of film T. With reference to FIG. 10, each pair of sensors is arranged to detect the position of the corresponding edge of film T within a set reading range, this detection signal being sent to a signal processing unit U which contains means to compare the measurements made. Since there are two pairs of sensors, the processing unit U makes comparisons by calculating the difference between the individual measurements (made at each of the opposing edges), and if a misalignment is found in relation to the longitudinal axis of the film, a control signal is generated to operate the corresponding motor 14 which, by moving the bracket 10 of redirecting arm 9 brings the film back into the centred position thus cancelling out the detected misalignment. Due to the presence of the double sensor, the film T is kept in a central position regardless of its actual transverse size. Furthermore, by selecting a pre-set sensor reading range, the extent of which is shown schematically by G in the figures, it is possible to guarantee detection of edges of film T that have variable widths and fall within a pre-selected range of dimensions, in any event within the reading range of the sensors.

The pairs of sensors L1, L2, R1, R2 in each film centring device of a corresponding wrapping row are conveniently of the analogue type. Returning to the group of wrapping film T feed reels B, with particular reference to FIGS. 14 and 15, each reel B1, 62 of each group of reels is associated with a film cutting device, marked 18 in the figures. This device comprises a rotating roller 18 a having a cutter along one of its generatrices and extending transversely to cut the entire width of the film. The operation of each roller 18 a is controlled by signals sent by the control unit U. Coupled with each cutting device there are also means for joining the cut edge of the film of one of the reels 81, B2 to the initial edge of the other reel 81, 82, so as automatically to drag the wrapping film of the second reel to the corresponding wrapping row. The control unit U contains means to generate control signals for cutting and joining the film in a synchronised manner for each group of reels so that the wrapping films of the second reels of each group simultaneously reach the respective wrapping rows, in order to affect the products P of a complete rank fed to the input station and consequently simultaneously to change the film for all the wrapping rows. In other words, when the wrapping film needs to be changed, for example in order to wrap batches of products with wrappers that have information and writing in a different language, it is necessary to be able simultaneously to change the wrapping films for each wrapping row. As the films cover different distances from the reel-carrier groups to the wrapping rows, the processing unit determines the times for cutting the films to be replaced in succession so as automatically to synchronise reel changing in each group and simultaneously change all of the films in all of the corresponding wrapping rows.

For the final stages of product wrapping, in which the wrapper wrapped round the product is cut to measure and welded at both longitudinal ends, the wrapping machine has, for each wrapping row, its own welding and cutting head, shown as a whole by 20. Only one of these heads will be described below as the heads are structurally identical.

With reference to FIGS. 5-7 and 11-13, each head 20 comprises a frame 21 on which are mounted a pair of welding and cutting rollers 22 a, 23 a. The rollers are rotatably supported in the frame and, by means of a pair of toothed wheels 22 b, 23 b respectively splined onto the respective roller shafts and engaging with each other, the reciprocal counter-rotational movement of the rollers is achieved.

Each roller also has a longitudinal projection 22 c, 23 c comprising a pressing element to cold weld the superimposed edges of the film. At this projection, there is also a cutting element 22 d, 23 d to cut the film.

Frame 21 is removably connected to a counter-frame 24 of the stationary structure of the machine so as to form an individually manoeuvrable unit, independently of the heads 20 associated with the other wrapping rows F. Frame 21 comprises a pair of opposing shoulders 21 a, 21 b which have guide profiles for the guided insertion into corresponding counter guiding means made in the counter-frame 24 of the machine. Thanks to this structure, the frame 21 slides in a guided manner in a direction Z perpendicular to the direction of advance X, from a non-operating position of extraction from the counter-frame 24 (FIG. 5) to an operating position inserted into the counter-frame of the machine (FIG. 6), in the inserted position the kinematic coupling of the toothed wheel 23 b with the respective motion transmission members being made. More particularly, for each head 20 there is a separate and distinct servomotor (not shown) to control the rotation, by means of a crown wheel 26 and pinion 27 gear, of a shaft 28 supported rotating in the counter-frame 24 of the machine, Splined to said shaft 28 is a toothed wheel 29 capable of meshing with the toothed wheel 23 b when the frame 21 is moved into the inserted operating position shown in FIG. 6. By means of this kinematic coupling, the rotational movement of rollers 22 a, 23 a is achieved. Toothed wheels 22 b, 23 b are advantageously housed inside the shoulder 21 b of frame 21.

30 shows as a whole a device for adjusting the contact pressure between rollers 22 a, 23 a. Each shoulder 21 a, 21 b is, for this purpose, divided into two structurally separate parts, each part being connected to the respective roller. A pair of springs 31 a, 31 b with their respective screws 32 a, 32 b for adjusting resilient stress, works on the respective projections 34 a, 34 b connected to the upper parts of the shoulders that support roller 22 b, The springs are also restrained by a plate 35 capable of being fixed to the upper parts of the shoulders of frame 21 as well as to the stationary structure of the machine.

Screws 32 a, 32 b, for adjusting the resilient load and coaxial with the respective springs 31 a, 31 b, are secured by a cylindrical joint to the respective projections 34 a, 34 b. When the frame 21 is in the inserted position (FIG. 6), by means of the adjustment screws it is possible to vary the active resilient load at the axial ends of roller 22 b (by lesser or greater compression of the springs), so as to adjust the relative contact pressure between the rollers at said axial ends.

It will be noted how each cutting and welding head 20, comprising an individually manoeuvrable unit, facilitates the assembly and dismantling operations of the heads, makes the heads of each wrapping row easily accessible, at the same time easing all the head adjustment operations as well as the operations required during maintenance. Furthermore, providing separate motorised units for each of the plurality of heads as well as for all of the other wrapping members makes it possible independently to control and operate each wrapping row, ensuring operation of the machine even if one or more of the rows should experience a stoppage.

The invention thus achieves the proposed aims providing the advantages described compared with the known solutions. 

1. A multiple-row machine for wrapping products (P), comprising a plurality of wrapping lines or rows (F), adjacent and coplanar to each other, each wrapping row being defined between a common input station (2) and a respective output station (3) for wrapped products, said rows developing parallel to each other along a direction of advance from the input station towards the output station, conveying means (N) being provided to convey the products (P), one in line with the other, along each respective wrapping line, the products being fed to the input station (2) in ranks at a set rate, each product of each rank engaging with each respective wrapping line at the same time, dragging means being provided on each respective wrapping row to drag a respective wrapping film (T) in an unwinding direction, wrapping means being provided to wrap the individual product (P) in wrapping film (T) and also to cut and weld the reciprocally superimposed edges of the wrapper, feeding the wrapped product to the output station (3), characterised in that for each wrapping row (F1, F2, . . . Fn) of said plurality of rows there are separate and distinct means (N1, N2, . . . Nn) of conveying products from said input station (2) to said output station (3), separate and distinct means of feeding the respective wrapping film (T) and separate and distinct means of wrapping the product (P), so that the entire product moving and wrapping stage, from the input station to the output station, is operated and controlled along each row (F1, F2, . . . Fn) independently of the other respective rows.
 2. Wrapping machine according to claim 1, wherein, for each wrapping row, there are distinct and separate first motor means to convey the products from the input station (2) to the output station (3), separate and distinct second motor means to feed the wrapping film (T) along the corresponding row, separate and distinct motor means to operate a respective pair of rollers (22 a, 23 a) to weld and cut the wrapper wrapped round the product (P).
 3. Wrapping machine according to claim 1, wherein there are nine wrapping rows (F), coplanar and parallel to each other in the direction of the output station.
 4. Wrapping machine according to claim 1, wherein, for each wrapping row (F), there is a respective group of reels (B) of wrapping film (T), said reels being arranged outside the wrapping rows with the axes of said reels parallel to the direction of advance of the products along the rows, so that the film (T) of each reel (B) is dragged along a first section transversely to said direction of advance and then redirected 90° back along a second section parallel to the direction of advance, a film centring device (16) being provided for each wrapping row (F), to keep the wrapping film (T) in a centred position in relation to the product (P) of the corresponding row.
 5. Wrapping machine according to claim 4, wherein, for each row there is an arm (9) to redirect the film (T) from the first to the second section, said redirecting arm (9) being positioned at 45° in relation to the unwinding directions of the first and second sections, the positioning of each redirecting arm (9) being adjustable, each centring device (16) comprising, downstream of the corresponding redirecting arm (9), a first (L1, L2) and second pair (R1, R2) of sensor means, each first and second pair being operationally associated with a respective side edge of the film (T) and being arranged to detect the position of the corresponding edge of the film (T) within a set sensor reading range, the sensor means being connected to a signal processing unit (U) containing means to process the signals of each pair of sensors for the corresponding film, so as to compare the measurements made on the opposite sides of the film and if a misalignment of the film in relation to a set central axis is detected, to generate a command signal to be sent to a motorised actuator (12, 14) located on the corresponding redirecting arm (9) in order to adjust the position of said arm (9) so as to move the film (T) towards a centred position.
 6. Wrapping machine according to claim 5, wherein said sensor means (L1, L2, R1, R2) are of the analogue type and have a reading range of an extent such as to guarantee edge detection for films (T) of widths that fall within a set range of measurements.
 7. Wrapping machine according to claim 1, wherein, for each wrapping row there is one pair of reels of wrapping paper with a first (B1) and second reel (B2) and an automatic reel-changing device (5), a film-cutting device (18) being furthermore associated with at least the first reel (B1) of said pair and means being provided to join the cut edge of film to the end of the film of the other second reel (B2), to drag said film (T) to the corresponding wrapping row (F), control means being provided to synchronise the cutting of the film on each first reel (B1) of said pairs of reels, so that the wrapping film of the second reels (B2) simultaneously reaches the respective wrapping rows in order to affect the products of a complete rank fed to the input station (2) and consequently simultaneously to change the film (T) for all the wrapping rows.
 8. Wrapping machine according to claim 2, wherein each pair of welding and cutting rollers (22 a, 23 a), associated with each respective wrapping row (F), is mounted in a frame (21) removably connectable to the structure of the machine so as to form an individually manoeuvrable unit, independently of the pairs of rollers (22 a, 23 a) of the machine's other wrapping rows (F).
 9. Wrapping machine according to claim 8, wherein said frame (21) has guiding means that can engage with corresponding counter guiding means (24) made in the stationary structure of the machine, so that said frame (21) can be moved in a transverse direction to the direction of advance from an extracted non-operating position to an operating position of kinematic coupling with the respective motion transmission members located in the machine's structure.
 10. Wrapping machine according to claim 9, wherein said frame (21) comprises at least one shoulder (21 b) inside which are housed respective toothed wheels (22 b, 23 b) splined to the respective shafts of said welding and cutting rollers (22 a, 23 a), one (23 b) of said wheels being mounted on the frame (21) in a position so as to mesh with a toothed wheel (29) operating the drive in said operating position. 